Studies are planned to study the effect of neurotransmitters, endocrine ablation and replacement, and stress on the "31K ACTH/Endorphin" molecule in hypothalamus. The first study will be performed in vitro, the last two types will be performed in brains derived from animals subjected to the indicated procedures in vivo. Additional studies will investigate the role of serotonin regulation of pituitary ACTH function, using immunocytohemical techniques in pituitary, as well as studying the effect of selective intrapituitary depletion of serotonin on pituitary-adrenal function. Additional in vitro studies will study the effect of neurotransmitters on pituitary ACTH release in the human. Studies will also be continued to ascertain stimuli that may effect Beta-endorphin release in the normal human subject, as well as studies of the levels and metabolism of this hormone in patients with chronic renal disease. Lastly, studies will be continued on factors (neuroanatomical, neuropharmacological) involved in the food restriction paradigm of generating adrenal corticosteroid circadian periodicity.